The proposed research is concerned with the total synthesis of cyclodepsipeptides of the surfactin and esperin type and the assay of the synthetic products for anticoagulant, hemolytic and antibiotic properties. Surfactin (from B. Subtilis) and esperin peptides (from B. mesentericus) have the same amino acid sequences but differ with respect to the size of their lactone rings and the structures of their alpha-hydroxy acid moieties. They may also have disparate configurational arrangements for their two leucylleucine residues. The presently accepted amino acid sequence for esperin is equivocal with respect to the configuration of the leucylleucine fragments. The surfactin sequence is not equivocal. Sequencing and amino acid configurational studies will be carried out on natural esperin peptides. A series of synthetic surfactin and esperin cyclodepsipeptide variants having systematic variations in their lipophilic portions will be prepared and tested for anticoagulant, hemolytic and antibiotic activity. Such variants may show selectivity in interactions with cell membranes and metal binding activity.